X-COM: Project Sigma
by Ausfer
Summary: X-COM 2: Project Sigma is an adult Viper fanfiction, based on X-COM 2. It's got sexy snake boobs, which is a perverted and shameful thing that you probably shouldn't read (but you will anyway). But its also got hard science—both real and speculative—and serious plot. If anyone finds the science getting in the way of enjoying the snek tits, I offer my deepest apologies.


**X-COM 2: Project Sigma**

"Hey Richard, why do the snake aliens have tits?"

In the last six years since I've joined the resistance, I've heard this question more than any other. I've had experienced soldiers ask me, I've had civilians who've survived an encounter ask me, and I've even had my fellow colleagues query my opinion on the matter. I would think that with all sorts of fascinating alien lifeforms currently occupying our planet—the disturbing Sectoids, the angelic Archons, or the enigmatic Elders—some of them would warrant public interest ... yet chances are, if someone stops by my lab to ask me a question regarding xenomorphology, more often or not, the topic is related to the breast-like protrusions on the chests of Vipers. I had no idea the question was on so many people's' minds.

I always gave the same answer: I do not know. To be perfectly honest, the question used to annoy me. I found it a distraction from my work, like a bothersome fly buzzing in my ear. But then the attack hit, and everything changed.

A mole in the resistance led ADVENT to our settlement, a punishment for our support of the rag-tag bunch running the revived X-COM project. As the portals opened and the aliens poured out, I witnessed horrors I would wish on no man. The brutish Mutons charged into the shantytown, bursting through walls like tissue paper, while ADVENT troopers herded up civilians in neat little lines and opened fire. And the Faceless ... god, I watched the grotesque transformation from human to pulsating, greasy monstrosity with my own eyes. I ran and hid in my lab, my quivering hands clutching an archaic magnum revolver from the old world. I hid as the screams of civilians and bestial cries of the extraterrestrials wormed their way through the air vents, and I wished with all my soul that I were more than one man with a pistol.

An icy dread froze my heart when I heard the lab doors slide open. I heard it long before I saw it: a terrible, serpentine hiss that would haunt my dreams to come. Glass test tubes shattered on the floor as it slithered over my desk, searching for human life. Somehow it knew to check the hazmat suit closet—maybe it could detect my body heat, or simply my scent. It threw open the doors and seized me with such speed that I could not pull the trigger in time. Its coils wrapped around my chest and squeezed. I felt my breath forced from my lungs, and heard the sound of my ribs cracking.

It could have crushed me within seconds. It could have even blasted me with its plasma weapon. But instead the creature was content to constrict and suffocate me, granting the occasional breath to draw my death out ever slower. And as it did so, it stared at me with those shockingly crimson, slit-pupil eyes. They flashed with the sharp spark of intelligence and perception. But though in those eyes I saw malice ... I also saw a curiosity in the way she watched me slowly choke to death. It almost seemed as if she was studying my reactions.

I do not know how long I stared into those reptilian eyes. As the minutes passed my grip on consciousness grew tenuous. My ears did not register the sound of heavy weapons, nor did I feel when my head hit the ground. But as I gasped for sweet oxygen to enter my lungs for the first time in forever, I found myself in the spasming coils of the now-dead Viper, looking up at a brave X-COM soldier offering his hand.

X-COM arrived in time to save roughly half our settlement. They brought out bodybags to take the extraterrestrial corpses back to their scientists. But the Viper I begged to keep. I needed to know why this creature gazed upon me with such interest when the legions of other alien species sought only to kill without mercy. After a lengthy argument with their field commander, he deferred me to their lead scientist: a well-learned but somewhat condescending geneticist by the name of Tygan. He kindly struck a deal: intel for intel, and I happily shared with him my life's work on sustainable aeroponics in exchange for the Viper corpse and his notes on the species.

I became determined to study this creature, and learn why it studied me.

I began the autopsy immediately. Removing the chest plate, I came face-to-face with those oddly prominent chest bulges ... I was reluctant at the time to call them breasts, but in hindsight that does seem to be the proper term. The ribcage was clearly more human than reptilian, even possessing the same number of ribs as a man. The prominent back muscles and narrow, feminine waist also seemed to be modeled after our own species. And though the creature was indeed female, instead of a reptilian cloaca near the end of the tail, I found instead a distinct vagina where a human's would go, hidden by labial scales just below the wide pelvis. Which means the rest of the Viper's body is essentially a very long tail.

The Viper's internal structure seemed roughly analogous to Earth creatures. Three lungs crowded the ribcage, and the bean-shaped liver—oddly white in color—connected to the neatly-coiled intestines. I almost mistook the two spleens for kidneys. The Viper's multi-chambered uterus connected to four ovaries. Even one ovary is enough to produce more eggs than any Earth creature could use in their lifetime, and I wondered if the organs serve another purpose. The jaw musculature was of impressive intricacy, capable of stretching wide enough to swallow animals whole ... perhaps even a small child.

The brain was a real treasure: three well-developed cerebral lobes. The prominent furrowing shares similarities with humans and other intelligent creatures. The olfactory bulbs took up a sixth of the total brain mass—Vipers must rely heavily on their sense of smell. Behind them, a well-developed prefrontal cortex ... an indicator of higher brain functions. The cerebellum was nearly twice the size in humans, owing to the thousands of limber muscles that required careful control. Though I struggled to identify the finer anatomical details of this alien's brain, I cut into what appeared to be the corpus striatum. Within, I discovered a well-defined striate nucleus housing copious substantia nigra. This suggests a high capacity for learning, planning, and reward-seeking behavior. Vipers must be a very perceptive and crafty race.

Perhaps this intelligent brain was why the Elders took such drastic measures to genetically modify the Viper into the humanoid Thin Man during the original invasion. Certainly, the more anthropomorphic Mutons and Sectoids lack the sophistication to understand and mimic complex human behavior.

My initial hypothesis regarding chest anatomy was that the breast-like protrusions housed Viper's poison glands, but upon dissection I found only fatty tissue, abundant nerves, and a tiny, vestigial ductal system: the parts were all there, but none of them are functional. The poison glands I found embedded in the Viper's cheeks, distal to the stretchy esophagus, and posterior to the incredibly long tongue, which lay coiled under the throat. I found no recognizable vocal chords, but not all animals need them to form a voice.

Compounding the mystery of the breasts, the notes given to me by Dr. Tygan mention X-COM running into exactly one male Viper, a product of human genetic experimentation. This male lacked breasts but was functionally capable of breeding (and quite often, apparently: the notes mention a cave full of laid eggs, hatched progeny, and a lively female harem). Tygan remarked that this incident was the only reported case of alien breeding, a feat largely thought to have been eliminated long ago by the Elders in favor of _in vitro_ fertilization. From this I drew three conclusions. First, Vipers are unique in retaining the ability to mate—a sharp contrast to the clearly genderless Sectoids, for example. Second, the Elders are either unwilling or unable to remove Viper sexual behavior from their gene pool. And third, the Elders field only female Vipers for their operations, otherwise Viper breeding would run unchecked.

I finished my autopsy with more questions than answers. Though this species appears more intelligent than perhaps any other alien life form save the Elders themselves, the Vipers seem content to aid in the systematic subversion and extermination of the human race. But why? Also, why had the Elders kept their ability to sexually reproduce, if they don't allow them to breed?

 _And why the heck do these snakes have boobs?!_

My curiosity remained unsated, and I resolved to take one step further in the pursuit of scientific knowledge: study of a live specimen.

... I formed that resolution four months ago.

A difficult four months it has been, but after much effort, I finally achieved my goal: a fully-sealed containment chamber built from scrap ADVENT technology, and a live Viper captured by resistance forces. The local guerilla leader gave me a great deal of grief for what her men had to do in order to bag the creature and transport it—all the way from ADVENT city twelve, they told me. However, I considered my monetary compensation rather generous. Plus, they got to keep her weapon and armor.

For sixteen days now, I've observed and studied my quarry from behind the glass—though, the shimmering, resilient wall is more accurately described as a rigid electrosensitive polymer with self-healing properties … ADVENT tech is impressive, to say the least. Bolted to the floor is a simple mattress, and a squatting toilet sits in the back corner—the best I could manage for her body shape. Though my subject has little in the ways of entertainment, when she behaves I let her watch streaming video from my desktop monitor.

She doesn't behave very often.

Sigma One, as I've come to designate in my notes, was at first very uncooperative, preferring to coil tightly next to the door and treat any stimulus with hissing and hostility. But as the days passed, she realized she was not in immediate danger and has since relaxed considerably. Even now she slithers from end-to-end of the chamber, watching from within the clear walls.

A fine specimen she is, Sigma One "stands" at some seven feet tall, though her total length measures closer to fifteen. If she'd let me take more exact measurements, I would. She looks far less menacing without her shingled armor plating. Her yellow and orange scales shimmer with a waxy veneer in the laboratory lights, and her red eyes are active and aware, instantly zeroing in on any movement.

Right now that movement is me. I grab the microphone stand and look up to her with a smile, my face an inch away from the glass-like walls. "Good evening, Sigma One. How are you doing?" My voice blares from the kludged speakers I salvaged from an aging holodeck. It had taken me a lot of soldering to get the setup working.

Sigma One jerks her head away to stare off in the corner, flicking her tongue out with a terse hiss. I know she can understand English—in fact, I've discovered she's fluent in multiple Earth languages, including Spanish, Japanese, Mandarin, and Hindi. Given the difficulty in learning such syntactically different languages, I wonder if such understanding is innate to these creatures, somehow written into their DNA by the Elders. However, Sigma One is unwilling to converse directly—the only word I've heard her say is "Yes". Perhaps the differences in her throat and tongue makes human speech difficult? I've been trying to surmount this obstacle for the past week, but Sigma One proves reluctant to cooperate.

"I have dinner for you, Sigma One, and also a special gift. But before I give them to you, you must promise to behave."

Her eyes briefly flash to mine before looking back into the corner.

"Well? Will you behave? You won't get to eat if you don't promise to behave."

Sigma One breathes a heavy exhale through her mouth. Her tongue flicks out as she deflates. Reluctantly, she nods.

I smile wider. "Good."

I place her dinner and gift in the airlock and seal it before opening her side. She looks at me with disdain but accepts the butchered pig leg anyway. She raises it above her head and her jaw distends as she swallows it whole.

As Sigma One eats, my eyes wander to the digital photostand on my desk. I stare back at a slightly younger version myself, a head of curly brown hair already thinning on top. I'm only thirty six; it's way too early for that. The hair almost obscures my sharp blue eyes. I am grinning wide. It exaggerates the dimple in my chin. My toned, hairy arms are wrapped around a beautiful woman wearing salvaged Kevlar and combat fatigues from the old world. Her name was Elizabeth Wilde. We had only been dating since March. She didn't survive ADVENT's raid four months ago. Muton plasma rifle to the chest. It nearly burned a hole right through her.

Life is tough out here in the resistance, and I've learned to let it go and move on. I'm still young, and—dare I say it, rather studly for a biologist—I'm sure I'll find someone eventually.

I notice Sigma One staring at me. She cocks her hips to the side and rests one hand on them—a very deliberate, very human mannerism. Lacking legs, the curvaceous widening below her belly can't even be called real hips, yet somehow this alien knows how to use them.

Sigma One clearly wants something. I pull my microphone over. "Aren't you going to look at your gift? I left it for you in the airlock."

Sigma One's eyes narrow. She re-enters the chamber, tongue flicking out. Her serpentine body rubs against it, and she picks it up. A modern tablet PC, with most of its features locked. It's made from a clear polymer with flexible circuitry, like the one I use. Much harder to smash than the last one. Whipping out my stylus, I record my observations regarding Sigma One's difficulty spotting the translucent tablet, and ponder whether Vipers can see the same spectrum of light we can.

Sigma One picks up the tablet and turns it on. A touch-sensitive keyboard appears on the surface and the holoscreen flickers to life. I'm pleased to see she does not immediately attempt to destroy this one.

"Well, go on. Type something on it. Try your name, Sigma One."

Looking thoroughly unamused, Sigma One plucks out a response on the keyboard with a single long finger. She hits "enter" and a monotone female voice emanates from the tablet, converting her text to speech.

"Sigma One."

Sigma One's cobra hood expands as she rears back in surprise. Her head then lowers and she glares at me. Her lips tighten as she realizes I've tricked her into conversing.

But her peevishness bothers me not. I've just experienced my first dialogue with an alien being! I know it's not the most tech-savvy way of communication, but hey, it works! My pulse races with excitement as I feverishly jot down my observations. "Well? What do you think?" I ask.

Cradling the tablet in one hand, Sigma One's other glosses lazily over the touchscreen, her clawed finger bobbing about like a lazy bumblebee in a flower patch. "I think you need to let me go, Doctor Reid," the robotic voice replies. She accents the reply with a snort.

I gasp in excitement. I can't believe I'm actually having meaningful conversation with an extraterrestrial! "Now, now, I can't do that," I say. "There's no telling what sort of mischief you'd get in to in this resistance camp—assuming you wouldn't get shot as soon as you slithered out of the lab."

"Oh, I know exactly what sort of mischief I'd get in to," replies the Viper, her mouth widening in an unsettling grin. "And I'd love to show you … if you'd just unlock the door." She flicks her tongue out and hisses.

The flat tone in the computer's voice did not do that reply justice, I think. Her sassy demeanor surprises me—in fact, I'm surprised this alien displays _any_ demeanor. Sigma One appears much more intelligent than I gave her credit for. Clearly, this species is well-adjusted to emulating human behavior … possibly a leftover bit of DNA engineering by the Elders, back when the Vipers were infiltrating our ranks under a humanoid guise. Or perhaps this behavior serves another purpose in the Viper's current role?

Sigma One hunches over her tablet and types. "When does the interrogation start, Doctor Reid?" She looks up, her red eyes burning into my own.

I smile. "I'm not here to interrogate you, nor punish you, nor torture you. I merely wish to study you."

Sigma One slithers up to me with lightning speed and pounds her open palm against the glass with a reverberating thud. She opens her mouth wide to hiss as she types. "You waste time studying me. They are coming. They are coming to devour while you fight us out of stubbornness and pride."

Indignation flares in my heart. "Of course we fight! We never asked to be subjugated, harvested, and experimented on! Humanity will always fight for their freedom … and not even you aliens can take it from us."

The Viper shook her head. "You are ignorant. They told us your species would cling to ignorance. Which is why we do what we do. We do not hate you. We do not wish to exterminate you. If you would only join us, like my people have, then you would understand the threat we face."

"We?" I sneer. "Don't act like you're on our side, like you care about our well-being. Everyone in the resistance has seen the horrors X-COM dug up—the human processing plants, the shipment of bodies in unmarked trains. I'd sooner die than join that!" I turn away, realizing I've let my emotions get the better of me. The last thing I want right now is to provoke her.

"Humanity ... we just want to be left alone," I mutter. "That's not asking much."

The Viper shrinks back. She coils up tightly and crosses her arms over her bare breasts. "I see we are at an impasse. Very well, then: in the meantime, examine me all you want, Doctor Reid. I am waiting." Sigma One grows still, staring with a disconcerting grin.

My heart leaps with joy. I pull my chair up to the glass and sit down, tablet PC and stylus in hand. There's a hundred things I could think to ask her. "Let's start with your species. You seem remarkably intelligent and free-willed compared to other extraterrestrials I've encountered. Why is that?"

Sigma One flicks her tongue out as she types. "Because we are not mere failed experiments. We follow the Elders willingly, because they are our only hope for survival. We are loyal to them, and they reward that loyalty by uplifting us, even though we cannot receive The Gift."

Fascinating. All this time I've been assuming Vipers were little more than slaves to the Elders. I record the revelation in my tablet. "X-COM has been calling you Vipers. Do you have a word for your species?"

Sigma One lets out an incomprehensible hiss of a word that I could not put into writing. "Next question."

I frown. "Where are you from? I mean, which planet?"

Sigma One performs an exaggerated yawn and stretches her unhinged jaws to a disturbing degree. "We have no planet. It is gone. Unless you join us, yours will eventually be gone, too."

The threat doesn't sit well with me, but I decide to avoid hostility. "Okay, Sigma One … how about we move on to—"

"Do not call me that. I do not like that name."

My ears perk up. For the first time in days, I feel like I have some modicum of leverage. I could hold a better name at ransom, but I decide to play nice. "What would you like to be called?"

The Viper ponders before typing in a response. "Siggy."

"Siggy?" I repeat, bewildered.

The Viper slithers over to me and puts a hand against the glass. "It is custom on Earth to shorten names in order to make them cute, is it not?" Her eyes narrow, and her lips widen in a disturbing facsimile of a human smile. "Sssss-geeee!" Her mouth opens in a wide grin as she attempts to rasps the word. Her breath fogs the glass.

I blink. So this extraterrestrial has some notion of what "cuteness" is. I jot the revelation down immediately. "You like … cuteness?" I ask. I think to myself that there's little about this creature that I could ever find cute.

Sigma One curls up comfortably in her coils and reclines against them. "What of it? Cute is a whimsical, pointless thing, yet humans are infatuated with it. I find that amusing. Next question."

I clear my throat and sit up straight. "Alright, Siggy …" I tentatively begin. "I'm very curious as to how an extraterrestrial so closely resembles the hooded cobra from Earth. Why is that?"

Sigma One leans back in her coils, arcs her back, and stretches her arms over her head with a fluid and limber grace. The tablet falls from whatever part of her anatomy serves as her "lap" and into her coils. I have to wait for her to finish stretching before she picks it up and lazily replies. "I'm more curious as to how your Earth cobras resemble my people."

I sigh. "Please answer the question, Siggy." Sigma One does not answer. Instead, she inspects her claws, like a woman examining newly-manicured nails.

I fidget in my chair. Sigma One does this often. Though I had initially considered it beyond her capabilities, I can't help but feel like this deliberate and well-rehearsed behavior is designed to annoy me. I feel like I'm being toyed with, as if it were me in the containment cell, not her. I don't like it.

"Siggy, did the Elders guide your evolution? Was it a conscious decision on their part to give your bodies distinctive Earth traits?"

The serpentine being stares at me. "I am as a tool, Doctor Reid. A tool does not how it was constructed, nor what came before it. A tool does not have ancestors to learn from, nor offspring to pass its knowledge to. A tool knows only the task it was designed for, and how to accomplish this task."

My writing hand flies across the surface of my tablet. So not only was this alien fluent in English, it also possessed the capacity to understand figurative language … not bad for a mere tool. "And before you were captured, what was your task, Siggy?"

Sigma One let out a snort. "To moderate my district's civilian dissidence algorithms, and to oversee the identification and removal of dissidents from society."

"So you help ADVENT snoop out and eliminate resistance sympathizers." I frown. "People like … me."

"Correct."

My stylus zips across my screen as I write my observations. That explains why Sigma One displays such intimate knowledge of human behavior and mannerisms. Humans have an awful lot of behavioral cues that the aliens can learn from and exploit, such as our tendency to avoid eye contact when we lie or feel guilty.

"Let's talk about your parts, Siggy, and why they were constructed. On Earth, cobra hoods evolved as a threat display. Why does your species have hoods?"

Sigma One flicks her tongue out from her scale-lined snout. "Hoods are attractive, Doctor Reid. Don't you agree?"

I nod in excitement as I write my observations. "So, are bigger hoods a sign of sexual fitness? A selective trait for desirable breeding partners?"

The Viper closed her eyes and relaxed in her coils. "We do not breed. The Elders prohibit it."

"Why?" Sigma One ignores me. "Why don't the Elders let you breed, Siggy?"

Letting out a grumpy snort, Sigma One pecks out a response on the keyboard propped up in her lap. "The genetic expression passed on by sexual reproduction is messy, random, and unmoderated. But the Elders refine our genome with a careful, efficient cunning. You know this, Doctor Reid. Do not patronize me."

Big words for a talking serpent tool. "Then why keep the hoods, if your people aren't allowed to breed?"

Sigma One glides one hand along her body, delicately tracing the curvature of her stomach and narrow waist. "The hoods now serve another purpose." she replied. "Humans interpret them as threatening."

I blink. So the Elders recognize the power of human fear. They understand us far better than I imagined. As I take notes, I notice Sigma One's free hand continues to explore her body. It travels up and gently cups one of her breasts. My eyes linger.

"And what about the breasts, Siggy?" I ask. "Why do you have those?"

Sigma One glances my way for the first time in a while. The corners of her mouth pull wide. "Breasts are attractive, Doctor Reid. Don't you agree?" She cocks her head and flicks out her tongue as she wagers my reaction.

I realize my cheeks feel a little warm. I brush it off. "They are on a _human,_ " I stress. "On an alien, it's just ... weird." Nevertheless, I can't help but feel a tad lewd as I watch her cup her bosom in hand and tenderly squeeze. "I'm willing to bet your species didn't have breasts before coming to Earth. Am I correct?"

Sigma One ignores my question. Her eyes are closed. She hisses softly as she fondles herself. One of her hands slide down her stomach and continues lower. I know where this is going.

Starting around the ninth day, Sigma One has displayed increasingly odd behavior. To be blunt, she has taken up masturbation. Rather liberally, as well. I initially attributed the behavior to restlessness and boredom … a sort of "cabin fever", but after careful observation of my video logs, I've discovered she only masturbates in my presence. I do not understand why, but I suspect that she's trying to … entice me, somehow.

I'm sure she noticed me taking copious notes during her first, shall we say … pleasure session. Truthfully, I was not aroused, being fully consumed in my fascination in this novel and unexpected behavior. Mayhaps she mistook my scholarly interest for desire, and now she sees it as a possible weakness of mine.

I've noticed that when Sigma One becomes aroused, the breasts gently swell and grow supple. The surprisingly perky nipples—normally hidden—appear from a seam in her chest scutes as they grow erect. Judging from Sigma One's fixation on them, they seem very receptive to pleasure, and I postulate their "tucked away" design keeps the nipples free from wear and tear, leaving them particularly sensitive. As arousal increases, the labial tissue below Sigma One's waist puffs outward, parting the labial scales and exposing the vagina. Also, Sigma One's already-high internal body temperature dramatically rises. During her longest sessions, the glass of the containment chamber has fogged up. Orgasms come frequently and are often quite dramatic—though I wonder if she may be exaggerating her squirming in order to catch my attention.

I've already recorded all of this in my electronic journal. There's no need to write this particular session down. Instead of interested, I find myself exasperated as Sigma One decides that self-pleasuring is more important than a ground-breaking alien-human discourse. She closes her eyes and hisses softly as her finger dances circles around her labial scales, while her other hand kneads her breasts.

I lean into the microphone. "Siggy, if you would please, answer the question." Ignoring me, Sigma One glides her fingers around the entrance to her vent, tracing in slow circles. The tablet once again falls into her coils with a clatter.

"Siggy!" I pound on the glass, startling her.

Her fingers linger for a while before finally grabbing the tablet. "What question?" she asks, flashing a look of faux innocence.

I let out a testy sigh. "This isn't a game, Siggy. Please ..."

"Oh, but it is a game, Doctor Reid," Sigma One corrects me. As she types with her left hand, her right goes back to its sensual massaging. "It's a game we've been playing since we met. I do so like games ... don't you?"

I purse my lips, unsure of how to reply. My eyes wander to her fingers. Spreading her labia, she slides a pair inside. They glide in effortlessly, her passage already having grown quite wet. It's clear her species does not require extensive foreplay to get in the mood.

I sit up in my chair and clear my throat. "Just answer the questions, okay? We were talking about why your species has breasts." I realize I am staring at them and pull my gaze away. "It seems rather out-of-place, given your reptilian qualities. Why do they exist?"

Sigma One gyrates her hips against her fingers, now knuckle-deep inside of her. Her hissing becomes more vocal. Her fingers explore her inner walls; I can see her pressing in all sorts of different angles. With her free hand, she manages to peck out a response. "My breasts exist for you, Doctor Reid." As the tablet reads aloud her words, Sigma One gently lifts one of them for display.

I blink. "Uh … what?"

"My feminine parts are lonely and need attention. If only someone would show them some love." Sigma One looks up at me as the tablet reads her last words, her red eyes full of desire. She even batted her eyes at me!

I stare, awestruck at how effortlessly this alien creature mimics human displays of desire. Sigma One drops the tablet and drives her fingers into her vent, arching her back and grasping her right breast to tug and squeeze her erect nipple. She establishes a steady rhythm, rocking her digits in and out as she spreads her inner moisture around.

The pieces fall into place for me. I see some truth in the serpent-tongued alien's words, as twisted as they may be. There's no denying the distinctly sexual features and behavior of this alien species are certainly unsettling. And now I wonder that perhaps this was exactly the Elders' intention.

Why do the Elders deprive the nightmarish Sectoids of clothes and armor, rendering them nearly feral? And why do the Elders grace the floating Archons with an intimidating, divine presence? It's for the same reason they grant a disturbing human femininity to the scaly Vipers. Each of these decisions were deliberate—each carefully chosen as different ways to poke at humanity's psychological triggers ... they want to get under our skin, to make us feel uncomfortable, afraid, or inferior. That makes us easier to control.

Perhaps the Elders understand the human brain even better than we do.

But I wonder if something went wrong in the Viper's current genome. Certainly, Sigma One's current behavior does not lend itself to ADVENT's goals. Sigma One retrieves her fingers from her slit, leaving a long, slick strand of moisture. She wraps her tongue around her digits and makes a show of licking them clean. Her head curls down to lap at her own entrance, gathering her juices on her bifurcated tongue before swallowing. She's angled her body such that I can watch her tongue's every move. The tip of her tail swishes along the floor. She clutches her hips tight. Her breasts bob with every breath. Using a pair of fingers, she spreads her slit wide, showing the pink flesh within. Tracing around the sensitive skin, her tongue slowly swirls in deeper and eventually plunges into her vent. That's a new trick, I think, and I grab my tablet.

She lowers her head until her lips touch her labia, and thrusts her tongue deeper. The muscular organ pulses rapidly, stiffening and wriggling around, eliciting long hisses from Sigma One's throat. I record my observations, noting my cheeks feel a tad warm. Truthfully, though put-off by the notion, a little part of me feels intrigued.

Sigma One notices my note-taking. The Viper uncurls herself and takes the tablet in her wet hands. "You seem content to sit and watch, Doctor Reid. But perhaps you would like to do more?" She holds the tablet to her chest as she rocks her fingers in her vent. Her fingers are slow and deliberate. Sensual, even.

"Really?" I cock my head to the side.

"Yessssss …" she hisses—her real voice, not the tablet's. Her fingers then fly across the keyboard. "All you need to do is open the airlock."

I smile. "And then what?"

"I'll let you touch me anywhere you want. And we can do anything you want."

"Would you suck me dry?"

Sigma One licks her fluid-smeared lips. "I would love to."

"Would you let me stick it in your scale-covered cooter?"

Sigma One gasps. "Yes, please, Doctor Reid!"

"Well, in that case ..."

Sigma One slithers close and presses against the containment cell with both hands. Her breasts flatten against the glass as she watches me with excitement. I walk over to my desk and flip a switch.

I smile as I pick the microphone back up. "In that case, I'm not playing your game."

Sigma One flinches. Her fingers fly across the keyboard, but I cannot hear what the robotic voice reads to me: I've shut off the microphone in her chamber. Her expression turns to rage as she realizes what I've done. She pounds on the glass with her fist, causing it to resonate with a dull thud. I simply stare back, smiling wide. She bares her fangs at me with a muffled hiss, then throws the tablet against the far wall. I see it crack and I wince. That's one more piece of equipment I'll have to replace.

I sit down at my desk and turn to my computer. This was not Sigma One's first attempted escape. She's tried to hotwire the airlock to open on command, attempted to clog the toilet with pieces of her mattress so I'd have to come in and fix it, and has even feigned death for three whole days by lowering her heart rate and body temperature into a state of thanatopsis.

But I've been smart and careful, and have countered her every move thus far: I welded the airlock access panel shut, dug up the plumbing pipes and cleared them, and my biometric scans were not fooled by her possum game.

This isn't even Sigma One's first attempt at using sex appeal to manipulate me. Believing it a farce, I expect her to drop the act and mope in the corner, but to my surprise, she ignores me and returns to self-stimulating. The anger in her eyes gives way to pleasure, and as she bends back down to use her tongue, I look away. I'll give her time to cool off before approaching her again.

Minutes pass. I spend the time transcribing my handwritten notes into typed text. It all goes into a large folder named "Project Sigma". In there are all her biometric readings and anatomical details, every notable behavior or action. There are weeks-worth of footage, and pages upon pages of research, notes, observations, postulations, and random musings. In a short few weeks I've learned so much about Viper biology and behavior that I've probably become Earth's foremost expert on the species! I let myself bask in a modicum of pride. In the old world, before the invasion, academia would give out awards for this kind of stuff.

Behind me, I hear the muffled thumps of Sigma One's writhing snake body as she squirms in the throes of orgasm. She can be violent when aroused. Scary, even. I continue my work for several minutes longer, but a distinct knock interrupts me. I turn around to see Sigma One up against the containment chamber's glass. Still aroused, judging from her erect nipples and puffy vent. She's pleading to me with her eyes.

Sighing in whimsy, I get up and approach. Sigma One is displaying an emotion I've not seen of her before: regret. She holds up the cracked tablet as the corners of her lips curl in a pout … or what could be counted for a pout with those scaly, rigid lips.

I grab my microphone. "You've broken two, Siggy. I can't trust you with another one."

Sigma One puts a hand up to the glass. And then I bear witness to an intelligent snake with boobs giving me the saddest puppy dog eyes she could muster. Which, to be honest, looked more like a wide-eyed snake caught in headlights. It's not her fault: humans are rather unique with their range of facial expressions.

But I get the gist and relent with a sigh. "Alright, alright … I'll lend you mine. But _only_ if you promise not to smash it. Deal?"

Sigma One nods in excitement.

"I mean it, you gotta promise."

Sigma One crosses her heart with a finger. I make a mental note to add that to the list of cultural gestures she's inexplicably aware of.

I bite my lip and try to rationalize what I'm about to do. "Okay, let me set it up."

Sigma One claps her hands, then snuggles up tight in her coils, eagerly awaiting her new toy. Though my mind screams doubts at her sincerity, I can't deny that I'm dying to talk with her more. My first conversation with a sentient extraterrestrial gave me an incredible rush, and I have many topics I'd like to discuss, such as the Elders, or ADVENT, or her opinion on the human race. Maybe I could even coax out some valuable information that X-COM could use. I make sure to backup my tablet's files on my desktop computer before setting up a guest account and locking nearly all the programs.

I grab the microphone. "I'm going to cycle the airlock. Stay back." I wait for her to retreat to the far wall before pressing the button.

The airlock was salvaged from a downed ADVENT cargo ship. Its design was basic, but it worked like a charm. At the push of a button, both doors lock and the air is cycled out. From there, I can control which door to open. If there's a problem I can disengage the safety, which allows for manual operation. I removed the interior control panel and used my soldering iron to jury-rig its trigger onto a small remote I keep handy. This was to prevent Sigma One from operating the doors herself.

The outer door I always keep shut. I press the button and watch the inner door slam close, but I hear a strange sound: a blaring, buzzing beep. A twinge of panic tightens in my chest as I fear the airlock has somehow malfunctioned. I look inside and see nothing wrong: the inner door looks just fine. Tentatively, I open and close the inner door again, and I get another beep. Weird, everything seems normal except for the beep. I try to open the outer door, but it won't budge. Ah, that must be the problem! I turn off the safety and force my side to open. I step in and set my tablet down on the floor.

And then I saw it: the broken tablet wedged in the groove of the door frame. The door had shut on her tablet, preventing the locking bolt from extending into the wall. I had not noticed sooner: its translucent material was hard to spot through the window. A terrible pit forms in my stomach as I realize in full what happened.

 _The outer door wouldn't open because the inner door failed to lock._

I swear. Sigma One is already at the inner door, sticking her nimble fingers in the crease and forcing it open. I turn and leap out of the airlock. I frantically mash the buttons for the outer door to close. But they don't, because the safety is off. I engage the safety and mash the button so hard my thumb turns white. The door shuts just as Sigma One slithers through, trapping her at the waist. The beep goes off once more. She grunts and strains to reach me. I back up, jaw agape in horror as Sigma One thrashes and struggles to slip her body out from the sliding door.

Oh god ... what have I done?

My magnum revolver. Where did I stash that thing?! I run around my lab ripping open cabinets and drawers. I find it underneath a pile of old papers. It's unloaded. Shit! My fingers fly for the bullets. Some fall to the floor with a metallic clink. I chamber a round, then a second. Then I—

Something wet and hot wraps around my neck and pulls me off my feet. I choke and gag as the Viper's tongue drags me across the laboratory floor. I see the gun on the floor, drawing farther out of reach by the second. I try to scream, but the tension around my neck stifles my voice.

Sigma One keeps a strong hold around my neck as she drags me to her. I attempt to pry the saliva-covered tongue from my neck but find it impossible to slip my fingers around. Sigma One wrenches the airlock remote from my hands and opens the outer door, freeing herself. She wraps me up in her coils and next thing I know, I'm caught in in a Viper's embrace, just like four months ago.

But this time, there's no X-COM soldier to save my life.

Sigma One releases her tongue's hold on my neck, and I gasp and cough for fresh oxygen. I watch as that impossibly long organ slides back into her mouth. Sigma One's serpentine body clutches me tight—almost tight enough to suffocate. Her face draws close to mine. She opens her mouth wide and hisses.

I never imagined I'd die like this. Not at the hands of the alien I've worked so hard to secure and study. But then I notice my tablet in her hands. She holds it up, looking like the smuggest damn snake in the universe as she types.

"You are mine now, Doctor Reid," the tablet says. Despite my tablet's monotone voice, I sense the delight in her words. Sigma One's coils relax just a little, allowing me some breath. Sigma One's tongue launches from her mouth, and she retrieves my revolver from across the room. She holds it up by the barrel with two fingers. "You shouldn't have this lying around, Doctor Reid. Someone could get hurt." She tosses the revolver into the airlock and locks it with my remote.

Her tongue flickers out many times, practically tickling my nose. "I've never had a chance to smell you until now. Your scent is … enticing." She leans in and draws her slimy tongue across my neck. I feel her hot breath moisten my skin. My heart is racing, pounding against the thick serpentine coils wound across my chest.

"Wish I … could say … the same …" I spit out. Actually—she didn't smell bad … but I wanted to be brave instead of screaming "Don't kill me!" like a little bitch.

I wonder just how far a Viper's jaw can distend, and if there's even enough room for me in that tiny little waist of hers. No ... she'll have to butcher me first. I thrash in her grasp, but she bares her teeth and hisses as her coils squeeze tighter. I gag and gasp for air, but my lungs cannot expand under the pressure.

"Do not struggle, Doctor Reid." She drags a claw down my cheek and guides my chin up, forcing me to look her in the eyes. Her slit pupils widen as she stares back with glee. "I need you to save your strength."

I relax and the coils loosen enough for me to breathe. I hang my head low and shut my eyes tight, accepting my fate. "You ... you aren't going to eat me, are you?" I mutter. "At least have the decency to kill me quick."

Sigma One's head rears back and gasps. Her fingers fly over the keyboard. "Eat you? Do you think of me as a primitive animal?" She wags a clawed finger in front of my face. "Shame, shame, Doctor Reid. I expected better from you."

The coils around me relax and my feet touch the ground. I gaze at her in amazement as she releases me from bondage. "You … you're letting me go?" I gawk in disbelief. My feet are glued to the floor. I expect her to strike if I so much as flinch.

Sigma One circles me closely, her darting tongue tickling my ears. "Not quite. There's no fun in playing a game without a challenge, Doctor Reid."

My spine goes rigid. "W … what? What do you mean?"

Sigma One slithers up to me face-to-face. Her eyes narrow as she holds up the tablet. It reads to me a single word.

"Run."

I don't give her a chance to reconsider and bolt for the exit. Vaulting over my desk, I plow through a stack of printed research notes, sending papers everywhere. Behind me, I hear a loud and threatening hiss that chills my bones. I dive under a lab bench as Sigma One launches herself forward, using her coiled body like a spring. She plows into the bench, sending an expensive microfabricator crashing to the floor. I scamper away on hands and knees. Sigma One tackles me around the waist. Her claws grip my lab coat and tear it. But I find her arms lack the strength to contain me, and I throw her off with ease. I dash for the door. Just as I get my hand on the latch, her tongue lashes around my ankle and I hit the ground hard. My nails dig into the floor as I am dragged away, screaming. Within seconds I find myself in her coils once more.

Sigma One brings her face to mine, hissing wildly. Her fingers dance on the tablet's touchscreen. "That was fun. But too short. Again."

My eyes widen as she releases me once more. I step back, unsure if I should even try. But a violent hiss and a show of fangs send me on my way, and I sprint for the door. Sigma One launches herself with surprising speed, crashing me into a table and knocking over rows of plants in aeroponic tubes. I skid against the hard floor. Sigma One is on me in an instant. She flips me on my back. Pinning my arms over my head, she slithers on top and puts her weight on me. Her scaly breasts mash against my face. She lets out a long and terrifying hiss.

"No, no!" my scream is muffled under her breasts. I muster my strength and manage to force one knee between me and her. Using the power in my legs, I pry her off and roll to my stomach. I scramble to my feet. Sigma One raises up to find me brandishing a fire extinguisher—the closest heavy object I could get my hands on. She regards my choice of weapon with a flaring of her hood and an angry growl. I throw it at her and dash for the exit. She dodges with uncanny grace and wraps me up once more. Damn this snake! Even without legs, she's too fast!

Sigma One's red eyes stare into my own with a satisfied glint. She's still got my tablet. Her claws dance on the keyboard. "Again." She uncoils me.

A terrible dread falls over me. I realize Sigma One's trapped me in a cruel nightmare: a prey's final moments of being caught by a predator and dragged to an imminent death. And she's forcing me to relive it over and over again.

But I'm done being her plaything. "No," I say.

Sigma One glares at me. She bares her teeth and hisses.

"Oh ... fuck me," I mutter.

Sigma One flinches, then flicks her tongue out, looking displeased. "Doctor Reid, I hoped we'd have more fun before moving on to that. But, if you insist ..."

"W-what?" I stammer, backing up. "What do you mean?"

Sigma One's grin is as sly as ever as she stalks me around the lab. I find my back against the wall of her containment chamber. She leans in close—close enough for her breasts to brush my chest. Her tail wraps around my ankles. She types on the tablet. "You drive a hard bargain, Doctor Reid, but alright: I'll fuck you."

My eyes bulge out of my skull. I can't even begin to process her words.

Setting the tablet down, Sigma One buries her snout in my neck and breathes my scent in deep. Her arms wrap jealously around my back, and her hips press against my own. Her hands go to my lab coat and she jerks it down, off my shoulders. My shirt is next: she yanks it over my head and off. I hear the stitching rip. She lays her palms on my broad pectorals. Her fingers run eagerly through my chest hairs. I glance up, seeing Sigma One's eyes wide with excitement. She explores the contours of my body with a rapturous desire as her tongue flicks out to taste my scent.

Even now, being shirtless and fondled by unfamiliar, four-fingered hands, I wonder if this is just another sadistic way for Sigma One to toy with me before she kills me. She can't possibly be serious, right? Sex? With a human?

Sigma One notices my rigidity. She picks up the tablet. As she types, her serpentine hips continue to sway and press against mine. "Now Doctor Reid, I've never fucked before, but in my free time I've researched humanity's plethora of holovids on the subject, and I am certain the male partner is supposed to reciprocate during foreplay." She takes my hand and places it on her warm bosom. "Touch me, Doctor Reid. Feel my body."

My hands are paralyzed from fear, but Sigma One wraps hers over mine and guides me in the basics of snake boob stimulation. Reluctantly, my other hand joins, and she watches me fondle her chest with glee. Despite the leathery scutes covering them, her breasts feel soft and inviting in my hands. I roll her smooth nipples between my thumb and index finger, pinching and tugging gently as I cradle her bosom with my palms. Sigma One closes her eyes and hisses in satisfaction, her hips are _still_ grinding against mine, and I realize with a mixture of horror and relief that she is actually serious about having sex.

A gasp escapes me as Sigma One slams me against the outside of her containment chamber. Her left hand dips lower, finding my groin. I'm not erect—my fear is still too strong to warrant much lust. I grunt as Sigma One squeezes my crotch uncomfortably tight. Her snout hovers an inch from my nose. I can smell her breath, feel it's warmth wash over my lips. Her pink tongue snakes out and caresses me under the chin. Her other hand remains firmly planted on my chest, pinning me to the glass.

As her claws trace the outline of my flaccid dick, Sigma One opens her mouth and slowly wraps her jaws around my neck. Fear floods my mind and my spine goes rigid as her jaws gently squeeze my throat. I feel her fangs articulate independently—each unfolding from the roof of her mouth, testing my skin as their needle-sharp points dig into my flesh. If my heart could race any faster, I'd burst.

And then, she nips me. I gasp in pain as she pulls away. I bring a hand up to my neck, finding two drops of blood. I'm relieved to see no trace of greenish venom: she's given me a dry bite. Sigma One licks her fangs, then goes in to lap up the blood from my neck. I have no idea if she's doing this to toy with me, or if it's some twisted way to show desire—but either way, I'm terrified.

My breath is stifled as her scaly hand slips down my pants. She grasps my manhood, and I see the disappointment in her face when she does not find a firm erection waiting for her. Sigma One watches my expression closely, judging my reaction as she attempts to arouse me. She squeezes and tugs hard enough to be painful. She notices I've stopped fondling her breasts, and pauses to drag my hands back to her bosom, admonishing me with a hiss. Minutes pass with no success on her part. She switches tactics, going lower to my sac. I shriek as she squeezes.

"Gentle, please!" my strained voice whispers. "Those are very sensitive to pain."

Sigma One rips her hand from my pants with a furious hiss. She grabs the tablet and types. "What is wrong with you? I thought male humans can attain an erection easily."

I wince. "Getting molested by a cobra lady isn't high on my list of turn-ons."

Sigma One glares at me. She lets out an angry snort as she types. "Tell me your turn-ons, that I may arouse your male parts."

As scared as I am, I can't help but snicker at her choice of words. "None of my turn-ons involve snake alien boobs," I counter.

Sigma One's eyes narrow to slits. She sets the tablet down. Her arms wrap over my shoulders. She closes in, once more teasing my chest with a brush of her bosom. "Tell meee …" she hisses. The words are difficult for her to pronounce, but I understand anyway.

I look away from her serpentine gaze and say nothing. The last thing I want to do is encourage her.

Sigma One's eyes burn a hole into my own. "Fffffine." I gulp. Snake alien or not, whenever a woman says "fine", it's usually a bad sign.

The coils around my legs loosen. She undos my belt and yanks my pants down. After fighting with my shoes, she has me fully nude in my lab. I can't imagine what'd happen if someone were to walk in on me now. I wrap my arms around myself and shiver in the clammy air. Sigma One circles me closely. I can see the gears in her head turning, a new plan forming.

Her tail slithers up my legs and around my chest. And then, to my surprise, her muscular body tightens. She hoists me inches off the ground, her limber tail spiraling down my body like an antique barber's pole. Her upper body descends to the floor, which she supports on her hands. Her head is level with my manhood. She leans in.

"W-wait, don't you dare!" I thrash in her coils. She squeezes me tight, preventing me from wiggling loose. I gag and struggle to breathe. "Not the fangs!" I manage to squeak out.

Sigma One ignores me. She draws close to my groin and takes a deep breath. Letting out a pleasured hiss, she inhales again, burying her nose in my crotch. My mind wanders back to the Viper autopsy I performed four months ago, and those large olfactory bulbs in the brain—she must be able to smell tons of things undetectable to a human nose.

And whatever she smells now, she likes it.

Her limber hand snakes up my leg. She wraps her digits around my sac. To my relief I find her playing nice this time, gently rolling the sensitive orbs in her palm. Her other hand starts a rhythmic tugging on my cock. I manage to tilt my head far enough to see over the scaly coil around my chest. I watch with disbelief at the slender yellow hand with black claws stroking my dick, and the cobra-hooded snake snout only inches away from the tip. Her red eyes are focused on it, her tongue is darting around it. She seems ready to strike.

"To be honest," I begin, "I'd be a little more into this if I could get a promise that you won't kill me later."

Sigma One looks up at me. She makes a crossing motion over her heart and lets out a cheeky hiss. She's given me no reason to trust her, but even so, I feel my shoulders relax. I think back to the rallying cry of ufologists before the invasion: I want to believe.

Sigma One's bifurcated tongue flicks out, sampling the tip of my penis. A reverberating thrumm wells in her throat as her tongue retreats into her mouth—an odd sound I've never heard from her before. She's exploring my body with more consideration this time: the tugging on my cock isn't as uncomfortable, and her sharp claws do not scratch. I can feel my body betray my mind as the tugging, the squeezing, and the feathery touch of her tongue assist in preparing my manhood for sex.

Sigma One can feel my budding firmness in her hand and she squeezes hard. "Yesssss," she hisses in delight. She's growing noticeably antsy: her upper body sways on the ground, her coils rhythmically squeeze me. The tip of her tail brushes against my cheek, almost like a sensual caress. Emboldened by my stiffening cock, each flick of her tongue progressively grows in confidence and force, until she's bathing my cock in wet, eager laps.

I gasp as her hot tongue wraps around my growing shaft. Showing remarkable control, the coiled tongue starts sliding back and forth, tugging, pulling, and squeezing me. The forked tip swishes over my sensitive head. Backing away, Sigma One looks up at me, jaw agape with two feet of tongue extended—a tongue that's somehow able to work my shaft better than any hand.

"Holy shit," I whisper. I start to wonder what else that tongue of hers could do.

Sigma One grabs the tablet off my desk. Her tongue slowly slithers back into her throat. "You taste good, Doctor Reid. But I want more." She watches my face for a reaction, and as my eyes bulge wide, her lips widen in a lascivious grin.

Letting out a terrifying hiss, Sigma One strikes. I grunt as her snout rams into my groin. She's taken every inch of my dick in a fraction of a second. Her mouth is hot as an oven, and thick saliva quickly coats my shaft. Using her jaws, she kneads and squeezes my girth. I can't deny how good this feels. I writhe in her squeezing coils—not out of panic, but pleasure. My erection grows ever harder.

Sigma One proves to be a quick study in fellatio. Or maybe she's just watched too many holovids ... how the hell did she manage to "research" human porn before getting captured, anyway? Her day job must be awfully boring ...

Sigma One uses her whole head to pleasure me, rocking her snout back and forth and rubbing my penis tip along the insides of her maw. Her two needle-like fangs lie folded against the roof of her mouth. Grunting, I struggle to peek over her coils and watch, mystified in seeing this snake-headed alien slurping away at my dick like a hungry calf at its mother's teat.

I grunt and flex as I shoot a spurt of pre-cum in her mouth. Sigma One opens her eyes and pulls back, her tongue lingering around my cock to gather up the fluid. A pleasured growl escapes her throat as she swallows. "Mmmore," she murmurs, and dives right back down on my cock. I can't help but moan as I feel her rope-like tongue explore. As her snout rocks against my crotch, the tongue descends, wrapping around my sac.

"Fffuck," I groan as the hot tongue cradles and strokes my balls. I squirm in her serpentine embrace, unable do much of anything else. My toes curl in the air. Sigma One hums deep in her throat as she pleasures me. Minutes pass, I can feel my orgasm budding. I'm not sure if I want to let it happen or not.

"If you don't stop, I'm gonna …" my words trail off. They're met with an enthusiastic squeeze of her tongue.

Completely ensnared by her coils, I realize there's little I can do but let the snake finish me, so I start rocking my hips back into her snout. This seems to excite Sigma One, who clenches her body around mine. Her tail tip is still caressing my cheek. I feel the pressure grow in my groin as her rope-like tongue fondles my sac. And it's still stretching further! I feel it slithering back up to wrap around the base of my cock. She's practically tied a knot around my junk, now, and the pulsing, tugging squeeze of that tongue is driving me crazy.

My pleasure blooms, and I can take no more. "I'm getting close," I groan. Sigma One responds immediately, quickening her movements in an effort to get me off. Her pulsing tongue drives me over the edge. She feels my cock stiffen in her mouth and she growls, sealing her jaws around me. Her tongue's tightened around my cock too much, building the pressure in my tubes. My eyes roll in the back of my head. I gurgle as pleasure overwhelms me. I groan as my hot seed overcomes the pressure and erupts deep in her maw. Sigma One tenses and grunts in surprise as another spurt splashes into her gullet. She sucks noisily, slurping and churring deep in her throat, constricting her mouth's muscles to guide my load down her gullet.

My orgasm dies down, and as my dick softens, Sigma One slowly pulls away. One last throb, and a final drop of cum lands on her snout. Her tongue is still tied around my balls and cock. It loosens with a slow and sensual glide, gathering up all my spent fluid in its curls before finally retreating to her mouth. Sigma One closes her eyes and hums as she swallows. She finally uncoils me and I fall against the outside wall of her containment chamber, putting a hand to my racing heart.

Sigma One rises to my height, drawing the semen off her snout with her tongue and licking it clean. She watches me as she does it, looking for a reaction, but I'm too dazed to manage one. Her fingers drift over to my tablet. She types something.

"That was delightful. But I expected more."

I gulp. "That's all I got ... for now," I cautiously add. I don't want to anger her.

Sigma One's gaze narrows. "Then it's my turn."

My eyes widen. "Wait, wha—"

Sigma One slams my back on the desk, causing the drawers to rattle and the digital photo to fall to the floor. She slithers on top of me until her slit rests above my neck, a good six inches away. The snake is heavy and I find it hard to breathe with her on my chest. Using a pair of fingers, she spreads herself open, revealing the tender pink skin and a wet vent. A round clitoris awaits just inside her passage, like the keystone in an arch. Sigma One types on the tablet lying next to my face.

"Stick out your tongue."

Tentatively, I do so. Her eyes narrow. "All of it," she types. She grabs a handful of my hair and pulls.

Straining, I extend it as far as it could go. I can't even touch my nose with my tongue, let alone reach her vagina from here. She'd have to lie on my face, but I'm not about to encourage that.

Growling in annoyance, Sigma One pinches my tongue with two fingers and attempts to pull more out. I wince in pain. Disappointment spreads across her face she realizes I have so little to offer her. She slithers off me and types on the tablet, glaring at me. "Pathetic. Not worth my time. And I've always assumed you humans were hiding more. Why did your species evolve such useless tongues?"

I sit up and shrug. "We don't need them, I guess. Our dicks make up for it."

I immediately regret those words as Sigma One's eyes flash with intrigue. She puts down the tablet and bends over me, grasping my saliva-covered shaft in her hand. "Shhhhhow me," she whispers, baring her fangs. At least, I think that's what she said. No wonder she prefers the tablet.

For better or worse, I feel like I could go for a round two, and Sigma One's stroking hand works me up. She pushes me farther onto my desk, knocking off the last few pens, papers, and equipment. My calves hang over the side. Her swaying, serpentine body parts my thighs. She rises up until that narrow little waist hovers over mine, and when she presses against my groin, I gasp as I feel a warm spot on her scales.

I stare back at Sigma One's reptilian face, the elegant cobra hood of yellow scales, her red, slitted eyes, and her always-fierce expression. A strange finality comes over me as I realize I'm actually about to have sex with this alien being. There's no turning back.

Sigma One grinds against my erection hard, spreading her already liberal fluids on me. Her longue tongue descends, slithering down her left breast, threading under to lift it up on display. The forked tips curl around her nipple and tug, and I think she's doing it purely to impress or arouse me.

To be honest, at this point I feel a little bit of both.

I reach down to grab my cock, but it's pinned tight against my belly. "Lift up," I grunt. Sigma One obliges, and her muscular body arches in the air. I take my cock and slide it up to her puffy entrance. I navigate by touch, moving past the smooth labial scales as they brush against the tip of my cock. I reach a tender wet spot—Sigma One's vagina.

I have no time to prepare. As soon as she feels it in place, she slams her snake-like body down. Gasping in rapture, she arches her spine so far back that her throat faces the ceiling. Her inner muscles clench around my cock. My hands squeeze her around the waist with a vice grip as the sudden stimulation overwhelms me. My eyes shut tight. Slowly, she acclimates, calming down and relaxing her body. Sigma One leans over me, hands placed aside my head. Her swaying breasts hang in front of my face. Her forked tongue flicks from her scaled snout, slipping out between her fangs. Even now, her swagger is impeccable. Her red reptilian eyes scream two simple words: I win.

That smug and satisfied glint in her eyes makes me realize just how much she's been working to reach this point in her game. She's spent hours—perhaps even days—preparing for it. Planning it. Anticipating it. And now that she's finally won, she's savoring every moment of the victory while I lie pinned under her coils.

I'm not entirely comfortable being in this position. But considering Sigma One's persistence, tenacity, and cunning, I'd much rather end up the subject of her lust than the subject of her wrath.

Sigma One arches her body up and begins her ride. She starts slow. Her movements are rough and haphazard at first, but she experiments and explores until she works out a smooth rhythm. I hang on to her waist, watching in amazement as her serpentine body undulates and wiggles on top of me. I hear her tail swishing along the floor, swatting my fallen pens and papers. My desk creaks from our combined weight.

Her soft vent radiates immense heat. She's tight around my cock; her inner walls have to stretch to fit my girth ... I think to myself that maybe male Vipers aren't well hung. Sigma One growls in deep satisfaction as she wiggles her body against mine. She coils more of her body on the desk for leverage, and soon her pace increases in tempo and ferocity until she's slamming against my groin hard, fitting as much of me inside her as she can. She grinds her labial scales against my skin, angling her hips to press her internal clitoris against my shaft. My cock rubs and pokes in different spots on each bounce, sending shivers of pleasure up her spine and causing her to squeeze her vaginal muscles. I'd be lying if I said it didn't feel amazing.

"Yessss ..." she hisses as she bounces up and down. "Yes!" It's one of the few words she can say without difficulty.

I find my hips starting to push back on every thrust. She reaches up with one hand to squeeze her tan breasts, but then has a better idea: she removes mine from her scale-covered waist and slides them up. Her eyes roll back and she shuts them tight, hunching over me as I gently squeeze them and tug at her nipples. Her mouth opens and her long tongue unfurls, swaying in the air with each thrust. My cock's gone rigid inside of her. Each serpentine roll of her hips sends a different part of her tight walls gliding against my girth. Sigma One twists left and right on every bounce with an incredible range of motion. Without stiff legs to limit her, she's free to move in nearly any direction imaginable.

We've only been at it for a few minutes, but Sigma One is already approaching orgasm. She puts a hand at the back of my head, staring intensely into my eyes. Her bouncing grows wild, almost out of control. I bring my legs up and wrap them around her body so she doesn't slide right off me. I can feel it approach—her vent quivers around my cock. Her snake-like body tenses up.

Sigma One squeals and clenches hard as she reaches climax. She arches her back to a degree reserved for contortionists. Pulling me with her, I'm forced to sit up. Her breasts mash against my face as she squirms and thrashes. Even in this position, her body's flexible enough that she's able to grind and hump against me. With my arms wrapped around her back, I clutch her tight as her vent clenches and spasms around my cock.

Just as she's starting to calm down, my lips find her nipple and I latch on, and to my surprise it gets her going all over again. She wraps a hand around my head and buries me in her bosom, hissing loud. Her grinding against my crotch turns to humping, and then she's bouncing on me once more. In a few short minutes she lets out a high-pitched screech of ecstasy as a second orgasm overwhelms her. Her coils clench and relax. I hear her tail tip thumping against the side of my desk.

God, her vent won't stop clenching! I'm in danger of popping out of her, so I bring my hands down to stabilize her hips. I hang on for dear life, face pressed into her breasts until at last the thrashing snake grows quiet and I feel her vent loosen its hold of my cock. Her hot fluids leak onto my balls.

Her arms wrap around my shoulders, and I realize she's holding me securely, almost intimately. I continue suckling her breasts, flicking my tongue over her sensitive nipple and running around it in circles. I hear her panting. I feel her hanging tongue brush up against my shoulders. She leans back to look at me.

"Hell ..." I whisper, "do you always orgasm that easily?"

"Yesssss ..." she hisses, grinning wide.

I think she's done, but Sigma One's serpentine body suddenly comes to life. She wraps me up and rolls both of us over. Propping her upper body on one elbow, she looks back at me with lust in her eyes, panting heavily but no less horny than before. Her breasts gently sag to the side. I feel her coil up between my legs and push against the small of my back, forcing me to lean over her.

I see what she wants and give her a hard thrust, driving my cock deep in her folds. I don't know what's come over me, but my body does, and in seconds I'm giving her wet pussy a hard and aggressive pounding. Her long tongue sways in the air as she watches me ravage her body, squealing and hissing in delight.

Fuck, I _really_ hope someone doesn't walk by the lab and hear her.

It only takes Sigma One a few minutes for another orgasm to bloom. She arches her back: her breasts rise in the air and her cobra-hooded head leans over the end of my desk. She growling like a wild animal. Her long fingers find her breasts and she clutches them tight as her vent clenches around my shaft. Her muscular body coils and thrashes, and I have to lay down and wrap my arms tight around the small of her back before she squirms right out from under me.

I notice we're sliding off the desk—her scales provide little friction to keep us in place. I yell but it's too late. Sigma One's head hits the floor and the rest of us quickly follow. I pop out of her and sit up, tangled in her coils. I feel a sudden chill on my erection as the cool lab air flows over the wet skin.

"Oops ..." I mutter.

A scaly hand wraps around my wrist and I'm yanked back on top of her. I straddle Sigma One's serpentine body and sit up. I gasp in surprise as her tail coils around my midsection. Looking no worse for wear, she flicks her tongue at me and hisses. Grabby fingers find my erect cock and squeeze hard.

"I presume that means you want me to keep going." I smile. She nods.

Once more I slide my cock into her vent, and I welcome the sudden warmth. I waste no time and take her forcefully. Sigma One lays on her back as I give it to her hard, each thrust rocking her body against the floor. She shuts her eyes tight, breathing in short, ragged puffs. I think to myself I need to finish—my cock's been rock hard for a while now. I don't hold back, diving deep into her wet vent with every thrust.

Yet before I can finish, Sigma One somehow achieves yet another orgasm. Her coils tighten around my stomach to the point of being painful, and her upper body quivers. Her tongue lashes about like a whip, smacking me in the cheek as her vent clenches uncontrollably around my cock. I think to myself that this has been the craziest, wildest sex I've had in my entire life.

It takes me a few more minutes before I finally feel a pressure rising in my groin. "I'm getting close," I sputter.

"Yesss!" Sigma One hisses in delight. "Seed meee!"

My thrusts grow slower, more powerful. I shut my eyes tight as her hot vent glides around my stiffening erection. The pressure grows, and I grit my teeth. I give her one final, gut-quivering thrust that rocks her entire body, and let loose my cum deep within her. Sigma One's eyes bulge wide as she feels me filling her up, and she clamps hard around my cock with her vaginal muscles. She sputters and squirms, twisting her upper body like a corkscrew, and even as I lay on top of her belly, she's so flexible that her breasts lie flat against the floor.

My whole body tenses as I shoot all I can muster into her sopping wet vent. Sigma One pushes with her arms against the ground and throws her head back, hissing wildly as I pump my seed into her. Her sharp claws dig furrows into the floor. The clenching of her vaginal muscles prolongs my orgasm until it starts to hurt. I collapse on top of her, thoroughly exhausted. My dick gives its last hurrahs—a few weak throbs—before finally growing still.

I did it. I fucked an alien. And it was surprisingly satisfying.

Sigma One untwists herself and lays flat. Her rope-like tongue is hanging out of the side of her mouth. About two feet of it rests limp on the floor, and I don't think she cares. Her chest rapidly rises and falls with each breath. Her coils are still wrapped around my stomach. Her body's so warm that I've broken out in a sweat, despite the cold air of my lab. Sitting on my knees, I lean forward on my hands and try to collect my wits.

"Holy shit," I muster. "That was intense."

Sigma One hums in agreement, looking too tired to muster any other response.

My back itches. And so do my arms. I notice the red marks—that's where her claws scratched me. I check my neck again to find the pricks from her fangs are crusted over with blood. My cock aches. I slip out of her steamy vent and look at the damage done. Our combined fluids are smeared all over her scales, and more leaks out of her.

Minutes later, Sigma One pushes her body up. Leaning back on one arm, her eyes drift to mine, and her mouth slowly spreads in a sly grin. I purse my lips tight. I don't know what that grin means.

Her coils flex and writhe, and I'm rolled onto my back. Sigma One leans over me. I watch as her tongue snakes down to my flaccid manhood. Coiling around my girth, she cleans my shaft of our combined mess in one single, sensual glide. With her eyes on me, she navigates by touch alone and moves on to her own body. She gathers the fluids up in coils of her tongue tip before drawing it into her mouth with a sublime hum of satisfaction.

"That's, ah ..." I struggle for poignant words and come up short. "That's quite a tongue you got," is all I can manage.

Sigma One's coils pull me on top of her. I'm an inch away from her yellow scaled snout. She flicks out her tongue and licks her sharp fangs. I gulp. Sigma One wraps tight around me until I'm covered in snake coils from the chest down. She lays me on the cold floor of my lab and she grabs my tablet that's since fallen off my desk.

"Sex is more than I imagined," she types.

"More what?" I cock my head.

Her red eyes widen with excitement. "More everything. I see why you humans are so obsessed with it."

I try not to laugh. "It's not just the sex we like," I say. "There's also the afterglow."

Her tongue flicks from her snout. "What is this afterglow?" she types.

"This." Reaching up to her, I pull Sigma One close. My hands wrap tight around her scaly little waist, and I gently guide her head to my chest. I can hardly believe I'm attempting to teach a snake alien how to cuddle, but I'm doing it anyway. Sigma One is stiff in my arms, like she's unsure of what to do.

"What is this?" she finally asks, after a minute of silence. "Are we waiting for something?"

"No. This is intimacy," I reply, and squeeze her gently.

"I do not understand intimacy. Is it like cute?"

I smile. "Whimsical, pointless, and humans are infatuated with it ... yep."

"I see," Sigma One replies. "Perhaps, there is more to humans than what the Elders teach us." She looks like she's about to type more, but then decides to set the tablet down. Her coils gently tighten, and she grows comfortable in my embrace.

I hold her and say nothing for a while, half-beside myself with awe at what I may have just accomplished: deep, intimate understanding between an alien and a human.

Minutes pass, and Sigma One pulls away to stretch. I let her go and she unwinds me from her embrace. Her fingers dance across my tablet.

"What is the local time, Doctor Reid?"

I crawl to my knees and shuffle over to my desktop computer. The screen flickers to life.

"It's 2:37 AM," I say, amazed. I lost track of time long ago.

Sigma One slithers up behind me, my tablet in hand. "I trust that most of the humans in this resistance camp are asleep by now?"

"Yeah ..." I push down on the desk and force myself onto my feet. "Why didn't you just check the time on my tab—"

Before I know what hit me, Sigma One strikes. She wraps me in her coils—this time, it's tight enough that I can't breathe. I see malice in her eyes. She types on my tablet. "I think it's time for you to sleep too, Doctor Reed."

My eyes widen. I thrash in her grip, but I cannot shake her. "No! Don't do this!"

Sigma One types on my tablet. "You know I can't stay here. I belong with ADVENT."

Sigma One's coils grow ever tighter. I tremble with rage. "You ... you promised you wouldn't kill me!" I seethe. As the air exits my lungs, she squeezes harder, and I can't replace what I lose. I don't even care. " _You promised!_ "

Sigma One bares her fangs and hisses in my face. She squeezes ever tighter, and the last of my air is forced from my lungs. Once more she types on my tablet. "Goodnight, Doctor Reid," the monotone voice says.

Quivering with rage, I stare into those slit-pupil eyes as my heartbeat struggles. The oxygen levels in my brain drop, my vision dims. Her eyes are the last thing I see before everything fades to black.

I flinch and rouse myself. My head throbs with a stabbing pain. I'm naked and shivering in the chilly, filtered air of my lab. Groaning, I roll to my stomach and force myself onto my hands and knees. My first thought is of pure elation: she actually let me live! But then I wonder ... how long was I out?

I stagger to my feet and immediately collapse in my computer chair as my lightheadedness gets to me. For the next few minutes I focus solely on oxygenating my body with deep, calm breaths.

When I am ready, I raise my head to see my lab has been trashed. Much of it was due to Sigma One's "games" before things turned heated, but I notice a few new things and gasp in shock.

In the center of the floor is a pile of smoking ash. All my Project Sigma research!

My hands fly to my desktop computer. A terrible pit forms in my stomach when I see every file related to Project Sigma has been deleted. My digital hand-written observations and notes, my video logs, my old autopsy, Tygan's report, Sigma One's biometrics ... everything! I do a scan of the hard drive and find she's wiped all unallocated data, making the files unrecoverable. My backup drive has also been wiped. I search the lab in a frenzy for my tablet PC, but I can't find it anywhere.

"No ... no no _NO!_ " I pound my fist on the desk had enough to send a spike of pain up my arm. All my work, all my ground-breaking discoveries and insight into the Viper species, ADVENT, and the Elders ... it's all gone!

Then I gasp. There's one thing she might not have checked: my observation camera. It's hanging from the ceiling, overlooking my computer desk and the containment chamber.

It's set to track movement and it's always running. The camera stores two hours worth of data and is programmed to back up the video on my desktop before rewriting. Those backups, she deleted, but maybe the local data is still there ... it won't be enough to recover my work, but at least I'll find out what happened after I passed out.

I rush to the camera and rip open the service panel. Removing the data chip, I pop it in my computer. Success! There's fifty minutes of untouched footage!

I pour over the video. Most of the recording is dedicated to our ... lewd actions. My cheeks grow red with embarrassment and shame as I watch myself fornicate with a scaly snake alien. I skip ahead until I arrive at the moment Sigma One attacks. And then I slow the footage down.

I watch myself grow limp in Sigma One's coils. She inspects me to make sure I'm out, then her serpentine body visibly relaxes—it's enough to let my unconscious body breathe. She turns to my desktop computer. Sigma One works quickly and efficiently, displaying an intimate familiarity with human computer systems. I give the occasional twitch in her coils. Several times she pauses to put a finger to my neck—she's checking my pulse.

I can hardly believe what I'm seeing: Sigma One is balancing a razor's edge with my life, letting me breathe just enough to keep me incapacitated without actually killing me. As she works, I appear to regain consciousness more than once, and each time she has to put me back under. At one point I'm even aware enough to start hurling obscenities at her. I can't remember any of this.

With her work at the computer done, Sigma One rummages through my desk drawers and pulls out my soldering iron. She lays me down gently, inspecting me one more time to make sure I'm still breathing. Slithering across the floor with surprising speed, she gathers up all the papers knocked off my desk and puts them in a pile. She turns on the soldering iron tosses it on the papers. They start smoking in seconds.

Picking up my tablet PC, Sigma One then turns directly to my camera. She raises her serpentine body up and looks directly into the lens. She types something onto the keyboard as my papers catch fire in the background. My tablet then reads her words aloud.

"ADVENT City Center Twelve, District Eight. Catch me if you can, Doctor Reid."

In the background, on the floor, I let out a groan. Her head jerks in the direction of my voice, then back to my tablet. She types one more thing, looks at the camera, and she lets out a saucy hiss.

"Don't keep me waiting, or I'll get lonely."

Sigma One's mouth widens in a sly grin. I realize I've come to hate that grin. I can never be certain if she's smiling from cruel sadism or playful teasing. Maybe she doesn't even know the difference.

Sigma One darts close and gives the camera lens a quick kiss. With tablet in hand, she zips to the exit. I watch in horror as Sigma One opens the door, peeks outside, then slithers away into the dark of night, clutching the only copy of Project Sigma against her chest.

Not even a minute later, I watch myself come to. The camera focuses on my nude body. I pause the video and push myself away from my desk.

My hands clench into trembling fists. I steel my resolve.

The game is afoot.

THE END

* * *

 _Like the story? Don't thank me, thank Firaxis. I'm fairly certain this story (and most of the Viper porn in general) wouldn't exist if there were no snek bewbs in the game._

 _I do not plan on writing more, but I left the ending open just in case something changes (and by that I mean: if someone throws a lot money at me, because I don't like writing porn enough to do it for free)._

 _With that being said, I hope you enjoyed what I've crafted! I put a lot of hours into this story, Sigma One's character was a ton of fun to write._


End file.
